Various systems are known for supporting loads on roofs, and for installing skylights and/or smoke vents into roofs.
The most commonly used skylighting systems are those which incorporate translucent or transparent closure members, also referred to herein as lenses, into a framework which penetrates the roof support structure and may be supported from within the building, with the result that the skylight closure member transmits ambient daylight into the building.
In the past, roof penetrating installations have required a complex structure beneath the exterior roofing panels and inside the building enclosure in order to support a roof curb to which the skylight lens was attached. Conventional skylight curbs are generally in the form of a preassembled box structure, which is mounted within a roof aperture. The retrofitting of such curb systems into an existing roof structure is problematic in that all known conventional structures have a tendency to leak water when subjected to rain due to installation details and complexities which are affected by installation techniques or workmanship.
U.S. Pat. No. 4,296,581, Heckelsberg, issued Oct. 27, 1981, teaches a roof structure having a series of metal panels having flanges that interlock when the panels are laid side by side and which are subsequently tightly seamed together to convert the individual panels into an integrated roof forming membrane. This roofing structure is mounted to the building purlins with clips and permits the panels to expand or contract in response to temperature and pressure changes.
U.S. Pat. No. 4,703,596, to Sandow, issued Nov. 3, 1987, and titled “Grid Skylight System”, teaches a grid skylight support apparatus that includes prefabricated grid row frames, each formed of connected beam supports which define a number of bays. Each bay has a skylight curb formed by upper flanges of the beam supports to receive a preassembled skylight unit. The sides of each grid row frame provide mating edges that can register with the mating edges of adjacent other grid row frames during assembly. The skylights have peripheral support skirts that register upon each bay and a light-transmitting skylight panel to cover the peripheral support. Cross gutters on each grid row frame, which are positioned between adjacent skylights, extend at angles toward the respective mating edges of the grid row frame for carrying rainwater to a main gutter channel formed by field-assembly of the mating edges of two adjacent grid row frames. The main gutter channel includes a pair of longitudinally extending gutter sections, each having a main gutter channel surface with a lower elevation than the elevation of the cross flow channel. Fasteners assemble the grid row frame mating edges together and a continuous seal is provided to prevent rainwater leakage at the mating edges of adjacent grid row frames.
U.S. Pat. No. 4,520,604, to Halsey at al., issued Jun. 4, 1985, entitled “Skylight Structure”, teaches a curb structure dimensioned to be passed through an opening in a roof and then attached in asserted moisture impervious relation to the roof from within a building interior. A skylight assembly including a frame, and light transmitting member secured to the frame is dimensioned to be passed through the opening and attached in a sealing engagement to the curb structure from within the building interior for covering the opening. The skylight assembly is then secured to the rafters and headers at an interior location. The frame includes upper and lower clamping jaws and spaced fulcrum links attached to the jaws for clamping the light transmitting member thereto. The lower clamping jaws include a channel which engages and is interlocked with the curb structure.
Other skylight systems, as contemplated in U.S. Pat. No. 4,470,230, by Weisner, provide a prefabricated skylight support curb that is formed to be a protective packaging for the skylight during shipment and then used as a curb for mounting the skylight on a roof. A prefabricated skylight support curb for supporting a skylight thereover has a bottom flange angled, upright sides, and a top lip round the top of the sides forming an opening through the curb. A skylight is adapted to cover the opening through the skylight support curb, and has a domed portion and a drip edge on the curb portion. The skylight curb portion is shaped to fit over a portion of the prefabricated skylight support curb angled upright portion and top lip. The skylight support curb is shaped to nest an accompanying skylight therein having the skylight curb portion adjacent to the interior of the skylight support curb angled upright walls to protect the skylight during shipping and storing.
Another skylight system, U.S. Pat. No. 3,791,088, Sandoz, at al., teaches prefabricated multiple dome unit or skylights and composite provided, where each multiple dome unit has several domes of transparent or translucent material mounted together on a common frame, and means are provided for assembling a plurality of such dome units into a composite thereof on a building, with the units lapped and interfitted so as to provide a continuous drainage system discharging to the exterior of the units in the composite assembly.
U.S. Pat. No. 4,621,466, by Sonneborn at al., teaches a flashing frame described for roof windows to be installed adjacent to each other with edges facing each other. Connecting flanges of the upper flashing members extend beneath the roofing and, if need be, lower flashing members and intermediary flashing members extend obliquely outwardly.
In today's world of mandated energy efficiency in all types of buildings, the metal building industry needs a more effective way to support skylights and smoke vents, thus to bring daylight into buildings, as well as a more effective way to support a variety of other loads on roofs which have ribs extending the lengths of the metal panels which serve as the outer surfaces of such roofs.
To ensure adequate daylighting, conventional skylight and smoke vent installations require multiple roof apertures which extend cut through and remove plural major elevations, also referred to herein as ribs, in standing seam and other roof panel profiles to make room for a corresponding multiple curbs which are conventionally used to support such skylight or smoke vent installations. These multiple curbs, each around a separate roof aperture, create multiple opportunities for water to enter the interior of the building, due to multiple apertures and the widths of the curbs, thus the cuts through the multiple ribs, as well as presenting the challenge to effectively seal the roof at the high ends of such curbs.
The traditional curb constructions and methods of attachment in most cases thus require that a complicated support structure be installed below the roof panel and inside the building enclosure, which can restrict the relative movement of the roof panels and the curb, as associated with thermal expansion and contraction of the overlying metal roof due to temperature changes and the like.
None of the prior approaches have been able to provide an installation system for multiple skylights which accomplishes the goals of economy and simplicity of installation and which works equally well for new buildings and as retrofits in existing buildings.